Adipokine levels in Cushing's syndrome;: elevated resistin levels in female patients with Cushing's syndrome

BACKGROUND Cushing's syndrome (CS) is associated with central adiposity, insulin resistance and impaired glucose homeostasis. Adipose tissue is thought to regulates glucose homeostasis via circulating adipokines, such as resistin, leptin and adiponectin, although their role in the insulin resistance associated with CS has not been established. DESIGN We examined the relationship between insulin resistance and adipokine levels in CS patients. We compared plasma levels of resistin, leptin and adiponectin in 10 women and four men patients with CS, with 14 health subjects matched for age, gender and body mass index. A subgroup of three women and four men with pituitary-dependent CS were re-examined at least 9 months after curative surgery. RESULTS CS patients had significantly more truncal fat and less lean body mass as assessed by DEXA compared to control subjects. Total cholesterol, triglycerides and insulin resistance, as calculated using the homeostasis model assessment of insulin resistance (HOMA-R), was significantly increased in CS patients. Of the adipokines measured, only resistin was significantly different between female CS patients and female control subjects (5.05 +/- 0.56 vs. 2.91 +/- 0.39 mug/l, P = 0.015). Curative surgery significantly reduced total body fat and truncal fat, leptin, total and low-density lipoprotien (LDL) cholesterol, glucose and HOMA-R. A reduction in both resistin and adiponectin was also observed but the differences between pre- and post-treatment levels did not achieve statistical significance. CONCLUSION Here we report for the first time that resistin levels are significantly elevated in CS patients and may be important in the insulin resistance associated with glucocorticoid excess.